(bug 10172) Move setting the "changed since last visit" flags out of the job queue:

(bug 10172) Move setting the "changed since last visit" flags out of the job queue:
* Move up the UPDATE query on wl_notificationtimestamp up to before scheduling the EnotifyNotifyJob
* Move up the SELECT query fetching the users to be notified to before the UPDATE, and use its result for a more efficient UPDATE
* Pass actuallyNotifyOnPageChange() and the EnotifyNotifyJob an array of user IDs
* Add UserArray::newFromIDs()